ABSTRACT
OBJECTIVE: To further understand the role of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANK-L) in rheumatoid arthritis (RA), we studied the levels of RANK-L and OPG mRNA in peripheral blood mononuclear cells (PBMC) and synovial tissue of patients with RA and controls. METHODS: RANK-L and OPG mRNA levels were measured in PBMC and CD4+/CD8+ T cell subsets of patients with chronic RA, osteoarthritis (OA), and healthy controls, using quantitative real-time polymerase chain reaction. OPG and RANK-L mRNA levels were measured in paired blood and synovial tissue samples of patients with early, untreated RA at 2 timepoints with an interval of 16 weeks. RESULTS: RANK-L mRNA levels were significantly higher in PBMC of patients with early and chronic RA compared to healthy controls. Contrary to healthy controls, RANK-L mRNA levels in patients with chronic RA were mainly of CD4+ T cell origin. OPG mRNA was observed in the blood of all (17/17) early RA patients, but could not be detected in chronic RA patients (0/14) or in patients with OA (0/8). Three out of 17 healthy controls showed measurable levels of OPG mRNA. The OPG/RANK-L ratio tended to be higher in the synovium than in the PBMC of early RA patients. RANK-L mRNA in synovial tissue was mainly of non-T cell origin. CONCLUSION: Since RANK-L and OPG mRNA levels are elevated in PBMC of RA patients, and CD4+ T cells are the major contributors to RANK-L mRNA expression, mononuclear cells in patients with RA may be involved in the pathways that regulate bone metabolism.
Subject(s)
Arthritis, Rheumatoid/metabolism , Glycoproteins/genetics , RNA, Messenger/metabolism , Receptors, Cytoplasmic and Nuclear/genetics , Adult , Aged , Arthritis, Rheumatoid/blood , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/metabolism , Carrier Proteins , Case-Control Studies , Female , Humans , Lymphocyte Activation , Male , Membrane Glycoproteins , Middle Aged , Monocytes/metabolism , Osteoprotegerin , RANK Ligand , Receptor Activator of Nuclear Factor-kappa B , Receptors, Tumor Necrosis Factor , Synovial Membrane/metabolismABSTRACT
OBJECTIVE: To study T cell receptor (TCR) repertoire changes in synovial membrane over a 16 week period in patients with early rheumatoid arthritis (RA); and to study the influence of cyclosporin A (CSA) on TCR repertoire in a subgroup of these patients. METHODS: Synovial tissue biopsies and paired blood samples were obtained from 12 patients with early RA at 2 time points. Seven patients were treated with CSA (Neoral-Sandimmun, 3 mg/kg/day) and 5 patients with placebo for 16 weeks. TCR V gene repertoires were analyzed by semiquantitative PCR-ELISA. CDR3 spectratyping and sequence analysis was used to compare TCR clonotype distributions. RESULTS: TCR-specific mRNA was detected in all synovial tissue biopsies at the first sampling, but in only 8/12 biopsies 16 weeks later (4/7 CSA group, 4/5 placebo group). Overrepresented TCR BV genes were found in biopsies of 10/12 patients at the first time point, and in 7/12 patients after 16 weeks (3/7 CSA, 4/5 placebo). CDR3 sequence analysis revealed dynamic repertoire changes with only a few persisting clonotypes in the synovial tissue of placebo controls. Persisting T cell clonotypes were more frequently found in the synovial tissue of CSA treated patients compared to the placebo group. CONCLUSION: These data suggest a dynamic process of T cell recruitment in the joints of RA patients. This process, possibly due to activation and subsequent infiltration of new T cell clones, apparently is influenced by CSA treatment. Synovial tissue T cells were no longer detected after 16 weeks' CSA treatment in 3 patients. In the other CSA treated patients, new T cell clones infiltrated, while other clones were persistently represented in the joints. These data may have important consequences for the design of T cell targeted therapies for RA.
